U.S. patent number 8,790,455 [Application Number 13/009,702] was granted by the patent office on 2014-07-29 for supersonic swirling separator 2 (sustor2).
The grantee listed for this patent is Anatoli Borissov, Geliy Mirzoev, Vladimir Shtern. Invention is credited to Anatoli Borissov, Geliy Mirzoev, Vladimir Shtern.
United States Patent |
8,790,455 |
Borissov , et al. |
July 29, 2014 |
Supersonic swirling separator 2 (Sustor2)
Abstract
Sustor2 provides deep cooling of a gas flow, practically total
condensation of a vapor, and fast and effective removal of the
condensed liquid with a significantly reduced pressure losses
compared with the prior art. Sustor2 performs the said operations
by developing a strong swirling flow starting from its entrance,
followed by spiral flow convergence in the inlet disc-like part,
and then in a converging-diverging nozzle, by centrifugal removal
of droplets, and removal of the liquid film through slits, then by
spiral flow divergence and leaving the vortex chamber through
tangential outlet. A gas enters from a pipeline (see the arrow in
the A-A cross-section shown in FIG. 7) connected to Sustor2 by a
flange and the inlet transition pipe ITP in FIG. 7, spirally
converged in the disc-like part, marked by A-A in FIG. 6, enters
the converging-diverging nozzle (FIG. 6). The flow is high-speed
and swirling even at the near-entrance region of the vortex
chamber. This swirl results in the centrifugal force that presses
the through-flow to the sidewall. The flow accelerates near the
nozzle throat up to a supersonic velocity with subsonic axial and
supersonic swirl velocity components. This acceleration results in
the gas temperature drop down to 200K and even less values. The
reduced temperature causes rapid condensation of vapor into
droplets. The centrifugal force pushes the droplets to the sidewall
where they are removed through slits. Next the dried gas spirally
diverges and leaves the vortex chamber through the tangential
outlet. This results in the pressure recovery and transformation of
the swirl kinetic energy into the longitudinal kinetic energy of
the gas. Both the effects decrease pressure losses which is the
Sustor2 advantage compared with the prior art.
Inventors: |
Borissov; Anatoli (Sugar Land,
TX), Mirzoev; Geliy (Sugar Land, TX), Shtern;
Vladimir (Houston, TX) |
Applicant: |
Name |
City |
State |
Country |
Type |
Borissov; Anatoli
Mirzoev; Geliy
Shtern; Vladimir |
Sugar Land
Sugar Land
Houston |
TX
TX
TX |
US
US
US |
|
|
Family
ID: |
46489762 |
Appl.
No.: |
13/009,702 |
Filed: |
January 19, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120180668 A1 |
Jul 19, 2012 |
|
Current U.S.
Class: |
96/389;
95/29 |
Current CPC
Class: |
B01D
53/002 (20130101); B01D 53/24 (20130101); B01D
45/16 (20130101) |
Current International
Class: |
B01D
51/08 (20060101) |
Field of
Search: |
;55/306,315,315.1,315.2,385.1,385.5,391,392,392.1,394-399,410,410.1,413-417,421,423-427,434,434.2,447,448,451,454,455-458,459.1-459.5,460,461-463,467,467.1,471,DIG.14,DIG.17
;96/301,302,314,321,355-360,365,366,372-379,389 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Goldshtik, M.A. and Shtern, V.N., "Collapse in Conical Viscous
Flows"; J. Fluid Mechanics, 1990, vol. 218, pp. 483-508. cited by
applicant .
Shtern, Vladimir, Borissov, Anatoly, and Hussain, Fazle; "Vortex
Sinks with Axial Flow: Solutin and Applications"; American
Institute of Physics 1997; Phys. Fluids 9 (10), Oct. 1997, pp.
2941-2959. cited by applicant .
Shtern, V., Borissov A., and Hussain, F.; "Temperature Distribution
in Swirling Jets"; Int. J. Heat Mass Transfer, vol. 41, No. 16, pp.
2455-2467, 1998. cited by applicant .
Borissov, A., Shtern, V., and Hussain, F.; "Modeling Flow and Heat
Transfer in Vortex Burners" American Institute of Aeronautics and
Astronautics Journal 97-1998, Jun. 29-Jul. 2, 1997; pp. 1-11. cited
by applicant .
Borissov, Anatoly and Shtern, Vladimir; "Combustion in Swirling
Flows"; 16th International Colloquium of the Dynamics of Explosions
and Reactive Systems; Aug. 3-8, 1997; pp. 278-281. cited by
applicant .
Shtern, V. and Borissov A.; "Nature of Counterflow and Circulation
in Vortex Separators"; American Institute of Physics, 2010; pp. 22,
083601-1-083601-9. cited by applicant .
Alfyorov, Vadim, Bagirov, Lev, Dmitriev, Leonard, Feygin, Vladimir,
and Imayev, Salavat; "Supersonic Nozzle Efficiently Separates
Natural Gas Components"; Oil and Gas Journal May 23, 2005; pp.
53-58. cited by applicant .
Schinkelshoek, Peter and Epsom, Hugh D.; "Supersonic Gas
Conditioning--Commercialisation of Twister.TM. Technology"; 87th
Annual Convention, Grapevine, TX Mar. 2-5, 2008. cited by applicant
.
Okimoto, Dr. Fred T, Sibani, Salim, and Lander, Michael; "Twister
Supersonic Gas Conditioning Process"; Society of Petroleum
Engineers, SPE 87262, Oct. 15-18, 2000. cited by applicant .
www.twisterbv.com/products-services/twister-supersonic-separator/how-it-wo-
rks/; "How it Works". cited by applicant.
|
Primary Examiner: Smith; Duane
Assistant Examiner: Turner; Sonji
Attorney, Agent or Firm: Amatong, Jr.; Alberto Q. The
Amatong Law Firm, PLLC
Claims
What is claimed:
1. A supersonic vortex-chamber separator arrangement comprising: an
inlet; an outlet a vortex chamber positioned between the inlet and
outlet and having a chamber axis, the chamber including a spiral
inlet portion in direct fluid communication with the inlet at an
intake end peripherally spaced from the chamber axis, a
converging-diverging nozzle positioned downstream of the first
spiral inlet portion and having a nozzle throat positioned
centrally about the chamber axis, and a spiral outlet portion
positioned downstream of the nozzle and in direct fluid
communication with the outlet at an exhaust end peripherally spaced
from the chamber axis; and wherein the vortex chamber further
includes a first disc shaped part positioned about a first axial
position on the chamber axis and a second disc shaped part
positioned about a second axial position on the chamber axis, the
first and second axial positions being spaced apart and the
converging-diverging nozzle being positioned therebetween; wherein
the spiral inlet portion is included in the first disc shaped part
and is positioned about the first axial position and shaped to
spirally converge gas flow about the second axial position and from
the inlet toward the chamber axis and the spiral outlet portion is
included in the second disc shaped part and is positioned about the
first axial position shaped to spirally diverge gas flow about the
second axial position outward to the outlet; and wherein the first
disc-shaped portion is further configured such that spiral flow in
the spiral inlet portion is maintained about the first axial
position until a turn shaped in the first disc shaped portion
directs flow away from the first axial position, toward the nozzle
and along the direction of the chamber axis to directly communicate
fluid flow from the spiral inlet portion to the nozzle.
2. The arrangement of claim 1, wherein the outlet is tangentially
directed relative to the chamber axis.
3. The arrangement of claim 2, wherein the inlet is tangentially
directed relative to the chamber axis and including a transition
pipe positioned to communicate gas flow tangentially relative to
the chamber axis.
4. The arrangement of claim 2, wherein the first disc shaped
portion includes an end wall enclosing the spiral inlet portion and
a profiled portion proximate the chamber axis shaping the turn, the
profiled portion extending from the end wall such that the turn of
the fluid flow at the profiled portion is directed away from the
end wall.
5. The arrangement of claim 2, wherein the spiral inlet portion
includes an axially directed central opening positioned about the
chamber axis and in direct fluid communication with an axially
converging section of the nozzle.
6. The arrangement of claim 1, wherein the vortex chamber includes
an axially diverging sidewall downstream of the nozzle throat, the
sidewall being equipped with a plurality of slits thereon for
passing condensed liquid from the gas flow and outward from the
vortex chamber.
7. The arrangement of claim 1, wherein the vortex chamber exhibits
a meridional cross-section characterized by and consisting of a
closed-end inlet section of the spiral inlet portion extending
peripherally from the chamber axis, an axially converging section
adjacent the closed-end inlet section generally exhibiting a
diameter substantially reduced from a diameter of the inlet section
and positioned upstream of the nozzle throat, a nozzle throat
section of reduced diameter, an elongated axially diverging section
downstream of and adjacent the nozzle throat, and a closed-end
outlet section of the spiral outlet portion adjacent the diverging
section and having a diameter generally extended from a diameter of
the diverging section.
8. The arrangement of claim 1, further including a second
converging-diverging nozzle positioned axially downstream of the
first nozzle, for fractioning of gas mixtures into components
having different dew points.
9. The arrangement of claim 1, wherein said vortex chamber defines
a profiled annular portion positioned about the chamber axis
between said first and second disc shaped parts and downstream of
said turn and in fluid communication with each of said spiral inlet
portion and said spiral outlet portion, the annular portion having
sidewalls that converge toward the chamber axis at the nozzle
throat and then, from the nozzle throat, diverge to the second disc
shaped part.
10. The arrangement of claim 9, wherein an axial distance from said
first axial position to said nozzle throat is less than a diameter
of said annular portion at said nozzle throat, and wherein an axial
length of a converging portion of said nozzle upstream of the
nozzle throat is less than an axial length of a diverging portion
of said nozzle downstream of the nozzle throat.
11. The arrangement of claim 9, wherein said annular portion and
said sidewalls thereof consist of a converging portion immediately
followed by a diverging portion and wherein said annular portion
defines an unobstructed circular flow-through cross section from,
and including, said converging portion to, and including, said
diverging portion, such that gas flow accelerates to supersonic
swirl flow velocity proximate the nozzle throat with subsonic axial
velocity.
Description
BACKGROUND OF THE INVENTION
A. The First Twister Separator
The closest prior art is the Twister Supersonic Separator (Trade
mark, February 2001, F. T. Okimoto and M. Betting, Twister
supersonic separator Proceedings of the 51st Laurance Reid Gas
Conditioning Conference, Norman, Okla., USA). FIG. 1 is a schematic
of the original Twister device. Its key feature is that a
swirl-free flow goes through a converging-diverging nozzle and
becomes supersonic. In this swirl free flow, water vapor condenses
into droplets due to decrease in temperature. Then this supersonic
flow becomes swirling due to an embedded wing.
Serious drawbacks of this Twister device are: 1. Droplets hit the
wing with a high velocity and thus eventually destroy it. The
Twister authors themselves pointed out that erosion of the wing is
a problem. 2. Droplets have a very small time to reach the wall
under the action of centrifugal forces because the length of
swirling flow is short compared with its swirl-free part. Our
estimate of the residence time shows that many droplets are not
separated and go with the "dry" gas in the Twister device. 3.
Twister does not permit a variable gas flow rate. 4. Significant
(30%) pressure losses.
B. The 3S Separator
An alternative approach is the 3S (Supersonic Swirling Separation)
technology developed by a group of Russian engineers (Vadim
Alfyorov et al., Supersonic nozzle efficiently separates natural
gas components, Oil & Gas Journal/May 23, 2005). FIG. 2 shows a
schematic of the 3S device. In contrast to the original Twister
device, here a flow first becomes swirling and then supersonic.
This important feature is common for the 3S and the Sustor
technologies.
The crucial difference is that the 3S technology uses a standard
Laval (subsonic-to supersonic) nozzle, as FIG. 2 shows, while the
SUSTOR technology uses a special nozzle which allows avoid the
occurrence of vortex breakdown (VB). VB is typical of swirling
flows and results in the appearance of a backward flow in a region
downstream of the nozzle as FIG. 3 illustrates. This VB destroys
the supersonic character of the flow in the working section due to
a shock wave (the red curve in FIG. 3) developing upstream of VB
and deteriorating the dehydration process. This limits the
application of the 3S technology to weakly swirling flows (where VB
does not occur). Since swirl is weak, the centrifugal effect is
small and therefore the separation of liquid droplets (resulting
from condensation in the supersonic flow) is inefficient. A
significant share of droplets is not removed through the peripheral
slit but is transported by the near-axis flow. These droplets
evaporate as the flow becomes subsonic and its temperature recovers
to its ambient value. Thus the dehydration is incomplete.
BRIEF SUMMARY OF THE INVENTION
A supersonic swirling separator (Sustor2) is a device making a gas
flow (1) swirling, (2) swirl focusing, (3) cold and dehydrated, (4)
swirl defocusing, (5) reheated and swirl-free. The device comprises
(a) a profiled manifold, (b) a tangential inlet, (c) a set of
tangential guides, (d) a vortex chamber, (e) a converging-diverging
nozzle, (f) a set of slits for removal of the condensed liquid, (g)
a tangential outlet, and (h) inlet and outlet flanges, connecting
Sustor2 to a gas pipeline. Sustor2 provides deep cooling of a gas
flow, practically total condensation of a vapor, fast and effective
removal of the condensed liquid, and efficient dehydration of the
gas. Sustor2 can be scaled to any flow rate, can be applied at a
separate gas well, has small pressure losses, and is cheap compared
to the prior art separators.
Supersonic Swirling Separator 2 (Sustor2) is a new device for the
continuous separation of vapors or/and gases from gas/gas mixtures.
Examples are dehydration, hydrocarbon dew pointing, and separation
of the different gases.
BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 describes Prior Art: schematics of the initial Twister
device.
FIG. 2 describes Prior Art: schematics of the 3S device.
FIG. 3 describes shock wave (red) developing in the prior
devices.
FIG. 4 describes schematics of the Sustor1 device.
FIG. 5 describes Prior Art: schematic of the improved Twister
device.
FIG. 6 shows the meridional cross-section of Sustor2 separator.
FIG. 7 shows the cross-sections A-A and B-B (see FIG. 6) of Sustor2
separator.
FIG. 8 shows the distribution of swirl velocity near the nozzle
throat of Sustor2.
FIG. 9 shows the distribution of axial velocity near the nozzle
throat of Sustor2.
FIG. 10 shows the distribution of the velocity vector projected on
the picture plane.
FIG. 11 shows the distribution of temperature near the nozzle
throat of Sustor2.
DETAILED DESCRIPTION OF THE INVENTION
The proposed invention--Sustor2 is based on research by each of the
authors as well as their collaborative research. The inventors have
long-term experience and expertise in dynamics of swirling flows
(e.g. see Borissov, Acta Mechanica 1990, Shtern & Goldshtik,
"Collapse in swirling flows" J. Fluid Mech. 1990). They worked
together a few years and published number of papers on mathematical
modeling of swirling flows (Shtern et al. "Vortex-sinks with axial
flow", Phys. Fluids, 1997, 9, 2941-2959; Shtern et al. "Temperature
distribution in swirling jets", Int. J. Heat Mass Transfer, 1998,
41 (16), 2455-2467; Borissov et al. "Modeling flow and heat
transfer in vortex burners", AIAA Journal, 1998, 36, 1665-1670; and
Borissov & Shtern, "Combustion in swirling flows", Proc. 16th
International Colloquium on the dynamics of explosion and reactive
systems, Krakow, Poland, Aug. 3-8, 1997, 278-281). At the end of
1999, Anatoly Borissov, Geliy Mirzoev, and Vladimir Shtern started
their collaborative experimental research on compressible swirling
flows for applications in gas-gas, gas-liquid, and liquid-liquid
separation. They developed the dehydrating apparatus Sustor1 (A. A.
Borissov, G. Mirzoev, and V. N. Shtern, Provisional patent
application 60/595,001, 2005). The authors' further insight in the
physical mechanism of swirling flows resulted in the development of
the apparatus Sustor2, which is the subject of this invention.
In contrast, the Sustor technology allows very strong swirl and
intense centrifugal separation. This makes the dehydration
efficient and the device to be compact.
The second serious limitation of the 3S technology is that it
allows no variation of the mass flow rate because the nozzle
cross-section area is fixed. Oppositely, the Sustor technology
allows the variation of the mass flow rate in a wide range.
C. The Sustor1 Separator
FIG. 4 shows the first Sustor separator, Sustor1 (A. A. Borissov,
G. Mirzoev, and V. N. Shtern, Provisional patent application
60/595,001, 2005). A gas enters Sustor from a pipeline connected to
Sustor by a flange, turns in manifold, passes through guides, and
tangentially enters vortex chamber with the central body the
plug.
Thus, a swirling flow develops in the annular gap between vortex
chamber and the cylindrical part of plug. The gap between the
vortex chamber and plug is a profiled annular channel with a
varying cross-section area. The outer and inner walls of this
channel form a converging-diverging transonic nozzle.
The removal of condensed water occurs through thin slits in the
peripheral sidewall (see narrow inclined channels in FIG. 4). This
water is accumulated in a tank. Conical diffuser serves for
pressure recovery. A flange connects diffuser with a pipeline.
A common feature of the Sustor1 and 3S devices is that the flow
first becomes swirling and then supersonic. An important difference
is there is the central profiled body in the Sustor1 (FIG. 4). This
body makes the Laval nozzle annular that should prevent the VB
development.
D. The Advanced Twister Separator
FIG. 5 shows a schematic of the advanced Twister separator (P.
Chinkelshoek and H. D. Epsom, Supersonic gas
conditioning--Commercialization of Twister Technology,
wisterbv.corn1wp--content/uploads/2008/03/twister--paper--gpa--march-2008
pdf). As FIG. 5 reveals, the improved Twister device incorporates
two important features of Sustor1: (a) in contrast to the original
Twister device, the improved device has the swirler located
upstream of the Laval nozzle and (b) in contrast to the original
Twister device, the improved device has the tapered inner body
which makes the nozzle annular. This changes decrease the pressure
losses. However, the losses are still large--25%.
There are two main factors causing the significant pressure losses
in the advanced Twister separator. The factor 1 is the shock wave
development and the factor 2 is that the swirling kinetic energy is
wasted due to viscous friction downstream of the cyclonic
separator.
The shock wave can develop even in a well-shaped supersonic part of
the Laval nozzle because the flow is swirling. A swirling flow
pattern can be very different with that of a swirl-free one. The
use of the central body prevents the development of the bubble-like
VB but does not exclude the flow separation. Swirl decay due to
viscous friction can induce a counterflow (Borissov & Shtern,
Phys. Fluids, 2010, 063601) as explained below.
The swirl-induced centrifugal force causes the radial pressure
gradient: the pressure near the center of rotation is reduced
compared with that at the periphery. Since swirl decays downstream,
the periphery-center pressure difference also decreases. This can
result in that the central pressure downstream exceeds the central
pressure upstream. This axial pressure gradient can cause flow
reversal not only near the axis, but also near the inner boundary
of the annular channel. The reversed motion induces the flow
separation from the inner boundary that in turn can result in the
shock wave development. The development of the reversed flow is
most probable in the diffuser (FIG. 5) because swirl rapidly decays
there due to the flow divergence. The circulation region initially
originating in the diffuser can then propagate upstream.
Understanding of the factors 1 and 2 is the fundamental background
of the development of the Sustor2 design described below.
Accordingly, several objects and advantages of the invention are to
provide an effective and complete separation of water and other
species (e.g., hydrocarbon condensates) from a natural gas with
relatively small pressure losses that obviates the disadvantages of
prior separators.
Specifically, Sustor2 is compact in size, enabling it to be used at
small gas wells, gas plants, gas storages, power plants, and so on.
Sustor2 does not leave liquid components, does not release any
harmful pollution, can be changed easily and conveniently for
variable flow rate, pressure, and temperature. Sustor2 is a
reliable, has no moving parts, requires no maintenance, and its
production is simple and rather inexpensive.
Key new elements of Sustor2, substantially different from the prior
art, are: Only swirl velocity becomes supersonic while the axial
and radial velocities are subsonic No shock wave develops that
significantly reduces pressure losses Swirl kinetic energy is
recovered that also reduces the overall pressure losses In
Addition, the Advantages of Sustor2 are: (1) the device is compact,
(2) can be scaled down for any rate of the gas flow, (3) can be
applied at a separate well (4) no re-compression is required.
Further advantages of Sustor2 will become apparent from
consideration of the ensuing description and accompanying
drawings.
A key element of Sustor2 is a profiled vortex chamber which
meridional cross-section is shown in FIG. 6. The chamber consists
of two disc-like parts AA, BB (marked by the A-A and B-B
cross-sections in FIG. 6) and the converging-diverging nozzle NZ
located in between. A gas enters from a pipeline, connected to
Sustor2 by the flange, Fl, shown in FIG. 7, goes through the
incoming transition pipe, ITP, and enters the vortex chamber VC
through the tangential inlet, TI, thus developing a swirling flow
inside the vortex chamber VC. The transition pipe ITP has the
circular cross-section at the flange FL Its cross-section geometry
changes eventually to rectangular one to fit the tangential inlet
TI, shown in FIG. 7.
The gas flow, entering the vortex chamber through TI, spirally
converges from the periphery toward the chamber axis YY, being
guided by the profiled sidewall and the profiled end wall, PEW, see
FIG. 6, turns (TT) into the converging-diverging nozzle NZ, passes
the nozzle throat NT, and then diverges, being attached to the
profiled sidewall DS, CS. As the gas flow reaches the disc-like
part BB, marked by B-B in FIG. 6, the flow spirally diverges,
leaves the vortex chamber VC through the tangential outlet, TO,
goes through the outcoming transition pipe, OTP, to the flange, FO,
and comes back to the pipeline (see the B-B part of FIG. 7).
A cyclone separator can be positioned between the pipeline and the
flange FI to remove solid particles and liquid droplets from the
incoming gas flow.
A modification of the preferred embodiment is a controllable inlet
(TI in FIG. 7). To this end, the inlet shaft, IS in FIG. 7, is used
that allows the end part of the TI wall to rotate around the shaft.
This would help to vary the gas flow rate while keeping the maximal
swirl velocity to be supersonic, as explained below.
The flow is high-speed and swirling even at the near-entrance
region of the vortex chamber. As the flow reaches the nozzle throat
vicinity, its swirl velocity reaches its maximum value. To better
explain the flow physics, the inventors performed numerical
simulations of a turbulent flow in a simplified model of Sustor2
device. FIG. 8 depicts the swirl velocity distribution near the
throat of a converging-diverging nozzle NZ. The throat diameter is
25 mm and other dimensions can be evaluated from the picture. The
gas flow mass rate is 50 g/s. FIG. 8 shows the velocity which is
normal to the meridional cross-section. The red (blue) color
corresponds to the velocity directed to (from) a viewer. As the
flow converges in the disc part of the device, the swirl velocity
increases, reaches its maximum near the throat NT, and decreases
downstream the throat NT.
FIG. 9 shows the axial velocity distribution and reveals two
important features: (a) the through-flow forms the annular conical
jet attached to the diverging part DS of the sidewall and (b) there
is a strong counterflow near the axis YY which is the most
high-speed near the nozzle throat NT.
FIG. 10 shows the velocity vector, projected on the picture plane,
and reveals that the flow consists from the two parts: (a) narrow
through-flow the near-sidewall jet and (b) circulation region which
is wide downstream the nozzle throat.
The physical mechanism of the circulation is the following. The
swirl-induced centrifugal force causes the radial pressure
gradient: the pressure near the center of rotation is reduced
compared with that at the periphery. The pressure reaches its
minimum at the device axis near the nozzle throat because the
centrifugal force is maximal there and diminishes as the sidewall
diverges. The fluid, located in the diverging part of the nozzle,
is sucked to the pressure minimum location and thus forms the
near-axis counterflow. This counterflow reflects from the end wall
PEW (marked by A-A in FIG. 6) and forms the meridional
circulation.
The strong adiabatic expansion in the converging part CS of the
nozzle cools down the gas to a very low temperature. FIG. 11
depicts the simulation results for the temperature distribution
near the nozzle throat. The temperature reaches its minimum value
in the jet-like through-flow slightly downstream of the throat. The
simulations shows that the minimum temperature (194K) is less by a
hundred Kelvin degrees than the ambient flow temperature
(300K).
Since the minimum temperature is significantly smaller than the dew
point value, practically entire water vapor in the gas rapidly
(nearly abruptly) condenses into droplets. The centrifugal force
(which is about million times gravity) immediately pushes these
growing droplets toward the sidewall. The droplets accumulate in a
water film on the sidewalls. The centrifugal force keeps this film
stable so water droplets do not come back to the gas flow that
drives the film downstream the nozzle where this water is removed
from the chamber through slits, marked by S in FIG. 6.
The performed simulations correspond to the pipeline pressure
exceeding the atmospheric pressure by 1 bar (this was made to match
the laboratory experiment). The industrial pipeline pressure is
hundred times larger than the atmospheric pressure. Accordingly,
the mass flow rate through the device increases from 50 g/s up to 5
kg/s. This value is of the same order of magnitude as that for a
typical gas well. To adjust to a real mass rate, a battery of
Sustor2 units can be applied. An alternative is to scale the
Sustor2 unit to the required flow rate.
The unit itself allows to vary the flow rate with no change in the
dehydration efficiency by using the controllable inlet (TI in FIG.
7). Let the swirl velocity becomes sonic at the fixed distance, r,
from the device axis while the gas flow spirally converges from TI
in the A-A disc part of the separator (FIG. 7). Note that r. is
close to the throat radius, rtr. During the rapid flow convergence,
the angular momentum is nearly conserved, .rho. vr=const, where
.rho. is the gas density, v is the swirl velocity, and r is the
distance from the axis. In particular,
.rho..sub.cv.sub.cr.sub.c=.rho..sub.iv.sub.ir.sub.i, where the
indices, c and i, mark the critical (sonic) and inlet values,
respectively. This yields the inlet velocity value, v.sub.i=v.sub.c
.rho..sub.cr.sub.c/(.rho..sub.ir.sup.i), which is fixed for the
prescribed geometry and conditions.
The gas mass rate is M'=.rho..sub.iv.sub.ih.sub.idr.sub.i, where
h.sub.i and dr.sub.i are the axial extent and the radial width of
the tangential inlet. Since h.sub.i is fixed, dr.sub.i must vary
proportionally to M': dr.sub.i=M'/(.rho..sub.iv.sub.ih.sub.i). Such
control variation of dr, can be made by using either manual or
automatic valve. The dashed line near TI in FIG. 7 indicates a
different position of the movable inner wall of the controllable
inlet.
Accordingly, it can be seen that Sustor2 provides effective removal
of vapor from a gas flow and has revolutionary advantages compared
with the prior art. Sustor2 is reliable, durable, maintenance-free,
environmentally friendly, and inexpensive device.
Although the description above contains much specificity, these
should not be construed as limiting the scope of the invention but
as merely providing illustrations of some of the presently
preferred embodiments of this invention. Various other embodiments
and ramifications are possible within its scope. Many other
ramifications and variations are possible within the teachings of
the invention. For example, the tangential guide vanes can be
applied in addition to the coiled transition pipe; the sidewall of
the converging-diverging nozzle can be differently profiled, e.g.
by including a cylindrical part; location of slits for water
removal can be different; and so on. Thus, the scope of the
invention should be determined by the appended claims and their
legal equivalents, rather than by the example given.
* * * * *
References